The telecommunications industry is in the process of developing a new generation of flexible and affordable communications that includes high-speed access while also supporting broadband services. Many features of the third generation (3G) mobile telecommunications system have already been established, but many other features have yet to be perfected. The Third Generation Partnership Project (3GPP) has been pivotal in these developments.
One of the systems within the third generation of mobile communications is the Universal Mobile Telecommunications System (UMTS) which delivers voice, data, multimedia, and wideband information to stationary as well as mobile customers. UMTS is designed to accommodate increased system capacity and data capability. Efficient use of the electromagnetic spectrum is vital in UMTS. It is known that spectrum efficiency can be attained using frequency division duplex (FDD) or using time division duplex (TDD) schemes. Space division duplex (SDD) is a third duplex transmission method used for wireless telecommunications.
As can be seen in FIG. 1, the UMTS architecture consists of user equipment 102 (UE), the UMTS Terrestrial Radio Access Network 104 (UTRAN), and the Core Network 126 (CN). The air interface between the UTRAN and the UE is called Uu, and the interface between the UTRAN and the Core Network is called Iu.
High-Speed Downlink Packet Access (HSDPA) and High-Speed Uplink Packet Access (HSUPA) are further 3G mobile telephony protocols in the High-Speed Packet Access (HSPA) family. They provide a smooth evolutionary path for UMTS-based networks allowing for higher data transfer speeds.
Evolved UTRAN (EUTRAN) is a more recent project than HSPA, and is meant to take 3G even farther into the future. EUTRAN is designed to improve the UMTS mobile phone standard in order to cope with various anticipated requirements. EUTRAN is frequently indicated by the term Long Term Evolution (LTE), and is also associated with terms like System Architecture Evolution (SAE). One target of EUTRAN is to enable all internet protocol (IP) systems to efficiently transmit IP data. The system will have only use a PS (packet switched) domain for voice and data calls, i.e. the system will contain Voice Over Internet Protocol (VoIP).
Information about LTE can be found in 3GPP TS 36.300 (V8.0.0, March 2007), Evolved Universal Terrestrial Radio Access (E-UTRA) and Evolved Universal Terrestrial Radio Access Network (E-UTRAN)—Overall description; Stage 2 (Release 8), which is incorporated herein by reference in its entirety. UTRAN and EUTRAN will now be described in some further detail, although it is to be understood that especially E-UTRAN is evolving over time.
The UTRAN consists of a set of Radio Network Subsystems 128 (RNS), each of which has geographic coverage of a number of cells 110 (C), as can be seen in FIG. 1. The interface between the subsystems is called Iur. Each Radio Network Subsystem 128 (RNS) includes a Radio Network Controller 112 (RNC) and at least one Node B 114, each Node B having geographic coverage of at least one cell 110. As can be seen from FIG. 1, the interface between an RNC 112 and a Node B 114 is called Iub, and the Iub is hard-wired rather than being an air interface. For any Node B 114 there is only one RNC 112. A Node B 114 is responsible for radio transmission and reception to and from the UE 102 (Node B antennas can typically be seen atop towers or preferably at less visible locations). The RNC 112 has overall control of the logical resources of each Node B 114 within the RNS 128, and the RNC 112 is also responsible for handover decisions which entail switching a call from one cell to another or between radio channels in the same cell.
In UMTS radio networks, a UE can support multiple applications of different qualities of service running simultaneously. In the MAC layer, multiple logical channels can be multiplexed to a single transport channel. The transport channel can define how traffic from logical channels is processed and sent to the physical layer. The basic data unit exchanged between MAC and physical layer is called the Transport Block (TB). It is composed of an RLC PDU and a MAC header. During a period of time called the transmission time interval (TTI), several transport blocks and some other parameters are delivered to the physical layer.
Generally speaking, a prefix of the letter “E” in upper or lower case signifies the Long Term Evolution (LTE). The E-UTRAN consists of eNBs (E-UTRAN Node B), providing the E-UTRA user plane (RLC/MAC/PHY) and control plane (RRC) protocol terminations towards the UE. The eNBs interface to the access gateway (aGW) via the S1, and are inter-connected via the X2.
An example of the E-UTRAN architecture is illustrated in FIG. 2. This example of E-UTRAN consists of eNBs, providing the E-UTRA user plane (RLC/MAC/PHY) and control plane (RRC) protocol terminations towards the UE. The eNBs are connected by means of the S1 interface to the EPC (evolved packet core), which is made out of Mobility Management Entities (MMEs) and/or gateways such as an access gateway (aGW). The S1 interface supports a many-to-many relation between MMEs and eNBs. Packet Data Convergence Protocol (PDCP) is located in an eNB.
In this example there exists an X2 interface between the eNBs that need to communicate with each other. For exceptional cases (e.g. inter-PLMN handover), LTE_ACTIVE inter-eNB mobility is supported by means of MME relocation via the S1 interface.
The eNB may host functions such as radio resource management (radio bearer control, radio admission control, connection mobility control, dynamic allocation of resources to UEs in both uplink and downlink), selection of a mobility management entity (MME) at UE attachment, scheduling and transmission of paging messages (originated from the MME), scheduling and transmission of broadcast information (originated from the MME or O&M), and measurement and measurement reporting configuration for mobility and scheduling. The MME may host functions such as the following: distribution of paging messages to the eNBs, security control, IP header compression and encryption of user data streams; termination of U-plane packets for paging reasons; switching of U-plane for support of UE mobility, idle state mobility control, System Architecture Evolution (SAE) bearer control, and ciphering and integrity protection of NAS signaling.
Incorporated herein in its entirety is TSG-RAN WG1 #50, R1-073842, Athens, Greece, Aug. 20-24, 2007: “Notes from uplink control signaling discussions.” In RAN1 #50 held in Athens, many assumptions related to control signalling on PUSCH were agreed upon.                Data and the different control fields (ACK/NACK, CQI/PMI) are mapped to separate modulation symbols. Here, ACK stands for acknowledgement, NACK stand for negative acknowledgement, and CQI stands for channel quality indicator.        Different coding rates for control is achieved by occupying different number of symbols        The coding rate to use for the control signalling is given by the PUSCH MCS. The relation is expressed in a table.        A table links each PUSCH MCS with a given coding rate for control signalling, i.e., the number of symbols to use for an ACK/NAK or a certain CQI/PMI size.Also incorporated by reference herein (in its entirety) is 3GPP TSG RAN WG1, Meeting #52bis, R1-081165 held in Shenzhen, China, 31 Mar.-4 Apr. 2008. Also incorporated by reference herein (in its entirety) is 3GPP TSG RAN1#52-Bis, R1-081295, Shenzhen, China, Mar. 31-Apr. 4, 2008: “Resource Provision for UL Control in PUSCH.” The multiplexing described above was further sharpened in RAN1 #52bis:        CQI/PMI on PUSCH uses the same modulation scheme as data on PUSCH        Semi-statically configured offset between the data MCS and the code rate of the control signaling is applied (A/N and CQI)        Next steps: Define the offset values. Discuss whether multiple offsets are needed e.g. when multiple services with different Quality of Service (QoS) are time multiplexed.        
The existing technology does not address how to link the PUSCH MCS and amount of resources for control on PUSCH, or how to guarantee sufficient quality for uplink (UL) control signals when multiplexed with UL data. There are certain issues which need to be taken into account when allocating resources for control signals:    1. Control Channel Quality            ACK/NACK and CQI have tight requirements in terms of B(L)ER performance        Re-transmission cannot be applied with control signals due to delay requirements            2. Data Dominance            Data quality defines the operation point for MCS selection and PUSCH power control        Control channels must adapt into the given SINR operation point        Information about the symbol split between data and control must be pre-known at both ends of the radio link in order to perform correct rate matching/de-matching and encoding/decoding operations for different channels            3. Different B(L)ER Operation Point            Data channel utilizes Hybrid Automatic Repeat Request (HARQ) and Link Adaptation (LA) whereas control signalling benefits neither from the fast link adaptation nor the HARQ        Channel coding        Data channel has Turbo coding and much larger coding block size        Control channel has relatively small code block size and smaller coding gain (ACK/NACK has only repetition coding)There is essentially no prior art available for detailed solutions for the problem described above. R1-081295 presents a formula to determine the size of control region based on the data MCS level. However there are several disadvantages in the solution presented in R1-081295. For example:        Useless term, Kc (can be combined with the offset parameter)        Useless function, log 2( ), (can be combined with the offset parameter)        “Un-defined” relationship between Data MCS and size of the control channel        No performance results are presented in R1-081295 to show the feasibility of this formula.These disadvantages require solutions in order to adequately solve the problems described above, and guarantee sufficient quality for UL control signals when multiplexed with UL data.        